Farmers' perception of the effects of earthworms on soil fertility and crop performance in southern CameroonThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Abstract

Summary The knowledge and perception of the effects of earthworms on soil fertility and crop growth was surveyed in a humid forest zone of southern Cameroon. A total of 215 farmers were interviewed in seven villages: two villages were near the capital Yaounde, severely deforested with a high land-use intensity, three villages were 60–100km south of Yaounde, moderately deforested with a medium land-use intensity and two villages were 130–200km south of Yaounde, mainly forested with a low land-use intensity. To assess if the fallow phase had attained sufficiently high levels of fertility, the status of the soil macrofauna was used by 42% of farmers as an indicator. The presence of earthworm casts was used by 35% of farmers to determine if the land was ready for cropping. Earthworms were not believed to have any effect on soil fertility (98.6%) and only 0.7% of farmers believed that earthworms either increased or decreased soil fertility. Across all crops, 71.6% of farmers reported that earthworms had no effect on crop yields. Any positive effects on yields were regarded as crop specific: 30.1% of farmers believed that groundnut (Arachis hypogaea) and cassava (Manihot esculentus) yields increased if earthworms were present. For maize (Zea mays) , plantain ( Musa spp.), cocoyam (Xanthosoma sagittifolium) and cacao (Theobroma cacao) , between 27.7 and 19.2% of farmers believed that earthworms created yield increases. Few respondents (mean across crops 1.8%) believed that earthworms decreased crop yields, with the greatest proportion of these relating to plantain (3.8%). The farmers' perception of earthworms' effects on cassava and groundnut yields was very dependent on the location and related to the levels of surface casting.